第七章 使用Tunnel实现组播负载均衡.doc

第七章 使用Tunnel实现组播负载均衡在单播路由表里，到达同一个目的地可以有多个下一跳，而在组播路由表里，到达同一个组，也可以有多个出口，但是这多个出口一定是到达不同的接收者，这是组播工作的一个基本特点。本测试主要研究在到一个组播接收者有多条等成本路径的时候，通过tunnel实现负载均衡。R2和R4之间有2条等成本的路径（通过调整COST实现），R4加入到组238.1.1.1，所有的路由运行PIM-SM，R1作为RP。具体实验拓扑：R1的具体配置hostname R1ip multicast-routing interface Loopback0 ip address 1.1.1.1 255.255.255.255interface Serial1/0 ip address 12.1.1.1 255.255.255.0 ip pim sparse-modeclock rate 64000interface Serial2/0 ip address 13.1.1.1 255.255.255.0 ip pim sparse-moderouter ospf 1 router-id 1.1.1.1network 0.0.0.0 255.255.255.255 area 0ip pim rp-address 1.1.1.1 R2的具体配置hostname R2ip multicast-routing interface Loopback0 ip address 2.2.2.2 255.255.255.255interface Ethernet0/0 ip address 10.1.1.2 255.255.255.0 ip pim sparse-mode ip ospf cost 64interface Serial1/0 ip address 24.1.1.2 255.255.255.0 ip pim sparse-modeclock rate 64000interface Serial2/0 ip address 12.1.1.2 255.255.255.0 ip pim sparse-mode router ospf 1 router-id 2.2.2.2network 0.0.0.0 255.255.255.255 area 0ip pim rp-address 1.1.1.1 R3的具体配置hostname R3ip multicast-routing interface Loopback0 ip address 3.3.3.3 255.255.255.255interface Serial1/0 ip address 13.1.1.3 255.255.255.0 ip pim sparse-modeclock rate 64000interface Serial2/0 ip address 35.1.1.3 255.255.255.0 ip pim sparse-moderouter ospf 1 router-id 3.3.3.3network 0.0.0.0 255.255.255.255 area 0ip pim rp-address 1.1.1.1R4的具体配置hostname R4ip multicast-routing interface Loopback0 ip address 4.4.4.4 255.255.255.255 ip pim sparse-mode ip igmp join-group 238.1.1.1interface Ethernet0/0 ip address 10.1.1.4 255.255.255.0 ip pim sparse-mode ip ospf cost 64interface Serial2/0 ip address 24.1.1.4 255.255.255.0 ip pim sparse-moderouter ospf 1 router-id 4.4.4.4network 0.0.0.0 255.255.255.255 area 0ip pim rp-address 1.1.1.1R5的具体配置hostname R5ip multicast-routing interface Loopback0 ip address 5.5.5.5 255.255.255.255interface Serial1/0 ip address 35.1.1.5 255.255.255.0 ip pim sparse-modeclock rate 64000router ospf 1 router-id 5.5.5.5network 0.0.0.0 255.255.255.255 area 0ip pim rp-address 1.1.1.1 我们来查看一下R2的路由表中4.4.4.4的路由信息：R2# sh ip route 4.4.4.4Routing entry for 4.4.4.4/32 Known via ospf 1, distance 110, metric 65, type intra area Last update from 10.1.1.4 on Ethernet0/0, 00:05:50 ago Routing Descriptor Blocks: * 24.1.1.4, from 4.4.4.4, 00:05:50 ago, via Serial1/0 Route metric is 65, traffic share count is 1 10.1.1.4, from 4.4.4.4, 00:05:50 ago, via Ethernet0/0 Route metric is 65, traffic share count is 1让R5做组播源，向R4发送组播数据包：R5# ping 238.1.1.1Type escape sequence to abort.Sending 1, 100-byte ICMP Echos to 238.1.1.1, timeout is 2 seconds:Reply to request 0 from 24.1.1.4, 72 ms如果路由配置正常，如上接收到R4的应答，我们查看一下R2的组播路由表：R2#show ip mroute IP Multicast Routing TableFlags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected, L - Local, P - Pruned, R - RP-bit set, F - Register flag, T - SPT-bit set, J - Join SPT, M - MSDP created entry, X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement, U - URD, I - Received Source Specific Host Report, Z - Multicast Tunnel, z - MDT-data group sender, Y - Joined MDT-data group, y - Sending to MDT-data groupOutgoing interface flags: H - Hardware switched, A - Assert winner Timers: Uptime/Expires Interface state: Interface, Next-Hop or VCD, State/Mode(*, 238.1.1.1), 00:08:50/00:03:06, RP 1.1.1.1, flags: S Incoming interface: Serial2/0, RPF nbr 12.1.1.1 Outgoing interface list: Serial1/0, Forward/Sparse, 00:08:50/00:03:06(35.1.1.5, 238.1.1.1), 00:01:08/00:02:25, flags: Incoming interface: Serial2/0, RPF nbr 12.1.1.1 Outgoing interface list: Serial1/0, Forward/Sparse, 00:01:08/00:03:06(*, 224.0.1.40), 00:11:22/00:03:07, RP 1.1.1.1, flags: SJCL Incoming interface: Serial2/0, RPF nbr 12.1.1.1 Outgoing interface list:Serial1/0, Forward/Sparse, 00:11:22/00:03:07可见R2仅仅使用了1条链路向R4转发组播数据包，在实际中有可能导致拥塞，可以测使用建立tunnel的方法来使用这2条链路分担流量。1：配置R2 R4的tunnelR2(config)#interface tunnel 10R2(config-if)#tunnel source 10.1.1.2R2(config-if)#tunnel destination 10.1.1.4R2(config-if)#ip unnumbered loopback 0R2(config-if)#ip pim sparse-modeR4(config)#int tu 10R4(config-if)#tu source 10.1.1.4R4(config-if)#tu d 10.1.1.2R4(config-if)#ip pim sparse-mode R4(config-if)#ip unnumbered loopback 02：不在R2、R4之间的物理链路上面运行组播R2(config-if)#int s1/0R2(config-if)#no ip pim sparse-mode R2(config-if)#int e0/0R2(config-if)#no ip pim sparse-mode3：清除R4的组播路由表R4#clear ip mroute *4：R4准备想RP方向注册组，但是RP的下一跳接口现在并未运行PIM，需要手动指定下一跳为tunnel，这样R4会把RP的注册信息丢弃。R4(config)#ip mroute 1.1.1.1 255.255.255.255 tunnel 105：在R5发起组播数据报文发送R5# ping Protocol ip: Target IP address: 238.1.1.1Repeat count 1: 100Datagram size 100: Timeout in seconds 2: Extended commands n: Sweep range of sizes n: Type escape sequence to abort.Sending 4, 100-byte ICMP Echos to 238.1.1.1, timeout is 2 seconds:Reply to request 0 from 4.4.4.4, 60 msReply to request 1 from 4.4.4.4, 72 msReply to request 2 from 4.4.4.4, 60 msReply to request 3 from 4.4.4.4, 72 ms以下省略因为Tunnel是基于物理链路的，所以数据包会在2条等成本的链路上负载均衡：R4(config)#access-list 120 permit gre any host 4.4.4.4R4(config)#access-list 120 permit ip any any R4(config)#access-list 110 permit gre an ho 4.4.4.4R4(config)#access-list 110 permit ip an an R4(config)#int s2/0R4(config-if)#ip access-group 110 inR4(config)#int e0/0R4(config-if)#ip access-group 120 in重复R5发送组播数据的过程，最后统计的结果如下：R4#show ip access-lists Extended IP access list 110 10 permit gre any host 4.4.4.4 （168 matches） 20 permit ip any any (58 matches)Extended IP access list 120 10 permit g